Legal claims defining the scope of protection. Each claim is shown in both the original legal language and a plain English translation.
1. A Channel State Information (CSI) feedback method of a receiver in a wireless communication system including a distributed antenna system, the method comprising: determining, by the receiver, a candidate Antenna Port (AP) set from among a plurality of APs; selecting an active AP set from the candidate AP set; and transmitting information on the candidate AP set, information on the active AP set, and downlink CSI of active APs included in the active AP set.
A receiver in a wireless communication system using distributed antennas determines a set of candidate antennas from all available antennas. From this candidate set, it selects a smaller set of active antennas. The receiver then transmits information about the candidate antenna set, the active antenna set, and Channel State Information (CSI) specifically for the active antennas. This allows the transmitter to optimize communication based on the best available antennas.
2. The CSI feedback method of claim 1 , wherein the candidate AP set is determined using slow fading.
In the Channel State Information (CSI) feedback method, where a receiver determines a candidate antenna set, selects an active antenna set from the candidate set, and transmits information on both sets along with downlink CSI of active antennas, the determination of the candidate antenna set is based on slow fading characteristics of the wireless channel. Slow fading represents long-term average signal strength variations, helping to identify antennas with generally good signal quality for inclusion in the candidate set.
3. The CSI feedback method of claim 1 , wherein the active AP set is selected from the candidate AP set using fast fading.
In the Channel State Information (CSI) feedback method, where a receiver determines a candidate antenna set, selects an active antenna set from the candidate set, and transmits information on both sets along with downlink CSI of active antennas, the selection of the active antenna set from the candidate antenna set is based on fast fading characteristics. Fast fading refers to short-term signal fluctuations due to multipath propagation, enabling the selection of antennas with currently favorable channel conditions from the pre-selected candidate set.
4. The CSI feedback method of claim 1 , wherein determining the candidate AP set comprises: estimating downlink channel matrices using pilot channels transmitted by the plurality of APs; calculating average channel gains using slow fading by averaging the channel matrices of the plurality of APs; and selecting the APs for which an average channel gain is greater than or equal to a first threshold value as candidate APs to be included in the candidate AP set.
Determining the candidate antenna set involves estimating downlink channel matrices using pilot signals transmitted by all antennas. Average channel gains are calculated by averaging the channel matrices, considering slow fading. Antennas with an average channel gain exceeding a threshold are selected as candidates. This pre-selection, based on long-term channel quality, reduces the complexity of subsequent active antenna selection.
5. The CSI feedback method of claim 4 , wherein selecting the active AP set comprises selecting APs from the candidate AP set for which a multiple of an average channel gain and an instant channel gain is greater than or equal to a second threshold value.
In the Channel State Information (CSI) feedback method, where a receiver determines a candidate antenna set, selects an active antenna set from the candidate set, and transmits information on both sets along with downlink CSI of active antennas, and where determining the candidate antenna set includes estimating downlink channel matrices, calculating average channel gains using slow fading, and selecting APs with average channel gain above a threshold, the selection of active antennas involves selecting antennas from the candidate set for which a combination of average channel gain and instantaneous channel gain exceeds a second threshold. This combines long-term and short-term channel quality to choose the best active antennas.
6. The CSI feedback method of claim 1 , wherein the downlink CSI includes average channel gain information of each active AP, relative channel difference information between active APs, and downlink CSI of each active AP.
The transmitted downlink CSI includes average channel gain information for each active antenna, relative channel difference information between the active antennas, and complete downlink CSI for each active antenna. This comprehensive feedback enables the transmitter to understand the individual strengths of each antenna, their relationships to each other, and the overall channel conditions for effective communication.
7. The CSI feedback method of claim 6 , wherein the downlink CSI of each active AP is expressed as information on a maximum singular vector of downlink channel matrix of each active AP, and wherein the information on the maximum singular vector is fed back to a transmitter using a weight vector closest to the maximum singular vector in a vector codebook.
In the Channel State Information (CSI) feedback method, where the transmitted downlink CSI includes average channel gain information, relative channel difference information, and downlink CSI of each active antenna, the downlink CSI for each active antenna is represented by the maximum singular vector of its downlink channel matrix. The receiver uses a vector codebook and sends the index of the closest vector in the codebook to the transmitter, allowing the transmitter to approximate the optimal transmission direction for that antenna.
8. The CSI feedback method of claim 6 , wherein the relative channel difference information between the active APs includes a quantized complex variable having a size of 1 bit.
In the Channel State Information (CSI) feedback method, where the transmitted downlink CSI includes average channel gain information, relative channel difference information, and downlink CSI of each active antenna, the relative channel difference information between active antennas is represented by a quantized complex variable of only 1 bit. This provides a compact representation of the phase difference between antenna channels, reducing feedback overhead.
9. A Channel State Information (CSI) feedback apparatus for a wireless communication system including a distributed antenna system, the CSI feedback apparatus comprising: a candidate Antenna Port (AP) set determination unit that determines a candidate AP set from among a plurality of APs; an active AP set determination unit that selects an active AP set from the candidate AP set; and a transceiver that transmits information on the candidate AP set, information on the active AP set, and downlink CSI of active APs included in the active AP set.
A Channel State Information (CSI) feedback apparatus for a wireless communication system using distributed antennas consists of three main components: A candidate antenna selection unit determines a set of candidate antennas from all available antennas. An active antenna selection unit selects a smaller set of active antennas from the candidate set. A transceiver transmits information about the candidate and active antenna sets, along with the downlink CSI for the active antennas.
10. The CSI feedback apparatus of claim 9 , wherein the candidate AP set determination unit determines the candidate AP set from among the plurality of APs using slow fading.
In the Channel State Information (CSI) feedback apparatus, which includes a candidate antenna selection unit, an active antenna selection unit, and a transceiver to transmit CSI, the candidate antenna selection unit selects antennas based on slow fading characteristics of the wireless channel. Slow fading represents long-term average signal strength variations, helping to identify antennas with generally good signal quality for inclusion in the candidate set.
11. The CSI feedback apparatus of claim 9 , the active AP set determination unit selects the active AP set from the candidate AP set using fast fading.
In the Channel State Information (CSI) feedback apparatus, which includes a candidate antenna selection unit, an active antenna selection unit, and a transceiver to transmit CSI, the active antenna selection unit selects antennas from the candidate set using fast fading characteristics. Fast fading refers to short-term signal fluctuations due to multipath propagation, enabling the selection of antennas with currently favorable channel conditions from the pre-selected candidate set.
12. The CSI feedback apparatus of claim 9 , further comprising: a downlink channel estimator that estimates downlink channel matrices using pilot channels transmitted by the plurality of APs; and a long-term channel gain estimator that calculates average channel gain using slow fading by averaging the channel matrices received from the plurality of APs, wherein the candidate AP set determination unit selects APs from among the plurality of APs for which an average channel gain is greater than or equal to a first threshold value as candidate APs to be included in the candidate AP set.
The Channel State Information (CSI) feedback apparatus, including a candidate antenna selection unit, an active antenna selection unit, and a transceiver, also comprises a downlink channel estimator and a long-term channel gain estimator. The channel estimator estimates downlink channel matrices using pilot signals. The gain estimator calculates average channel gain using slow fading. The candidate antenna selection unit then selects antennas with an average channel gain exceeding a threshold as candidate antennas.
13. The CSI feedback apparatus of claim 12 , wherein the AP set determination unit selects APs for which a multiple of an average channel gain and an instant channel gain is greater than or equal to a second threshold value as active APs to be included in the active AP set.
In the Channel State Information (CSI) feedback apparatus, where the candidate antenna selection unit selects antennas based on a threshold of average channel gain calculated using slow fading, and there's a downlink channel estimator and long-term channel gain estimator, the active antenna selection unit chooses active antennas from the candidate set if a multiple of their average channel gain and instantaneous channel gain exceeds another threshold value. This combines long-term and short-term channel quality to choose the best active antennas.
14. The CSI feedback apparatus of claim 9 , wherein the downlink CSI comprises: average channel gain information of each active AP; relative channel difference information between active APs; and downlink CSI of each active AP.
The transmitted downlink CSI in the apparatus includes average channel gain information for each active antenna, relative channel difference information between the active antennas, and complete downlink CSI for each active antenna. This comprehensive feedback enables the transmitter to understand the individual strengths of each antenna, their relationships to each other, and the overall channel conditions for effective communication.
15. The CSI feedback apparatus of claim 14 , wherein the downlink CSI of each active AP is expressed as information on a maximum singular vector of downlink channel matrix of each active AP, and wherein the information on the maximum singular vector is fed back to a transmitter using a weight vector closest to the maximum singular vector in a vector codebook.
In the Channel State Information (CSI) feedback apparatus, where the transmitted downlink CSI includes average channel gain information, relative channel difference information, and downlink CSI of each active antenna, the downlink CSI for each active antenna is represented by the maximum singular vector of its downlink channel matrix. The apparatus uses a vector codebook, and the index of the closest vector in the codebook is sent to the transmitter, allowing it to approximate the optimal transmission direction for that antenna.
16. The CSI feedback apparatus of claim 14 , wherein the relative channel difference information between the active APs is a quantized complex variable having a size of 1 bit.
In the Channel State Information (CSI) feedback apparatus, where the transmitted downlink CSI includes average channel gain information, relative channel difference information, and downlink CSI of each active antenna, the relative channel difference information between active antennas is a quantized complex variable with a size of 1 bit. This provides a compact representation of the phase difference between antenna channels, reducing feedback overhead.
17. A Channel State Information (CSI) processing method of a transmitter in a wireless communication system including a distributed antenna system, the CSI processing method comprising: receiving information on a candidate Antenna Port (AP) set including candidate APs selected from among a plurality of APs; receiving information on an active AP set including active APs selected from the candidate AP set; receiving downlink CSI on the active APs; and determining a maximum singular vector of downlink channel matrix for the plurality of APs using the downlink CSI on the active APs.
In a wireless communication system using distributed antennas, a transmitter receives information about a candidate antenna set, which is a subset of all antennas. It also receives information about an active antenna set, selected from the candidate set. Additionally, it gets downlink CSI for the active antennas. Using this CSI, the transmitter determines the maximum singular vector of the downlink channel matrix for all antennas, to optimize transmission.
18. The CSI processing method of claim 17 , wherein the candidate AP set is selected in consideration of slow fading, and wherein the active AP set is selected from the candidate AP set in consideration of fast fading.
In the Channel State Information (CSI) processing method of a transmitter, where information on candidate and active AP sets and downlink CSI is received and used to determine a maximum singular vector, the candidate antenna set is selected considering slow fading, which represents long-term signal strength. The active antenna set, a subset of the candidate set, is then selected from the candidate set considering fast fading, reflecting short-term channel variations.
19. A Channel State Information (CSI) processing apparatus of a transmitter in a wireless communication system including a distributed antenna system, the CSI processing apparatus comprising: a feedback receiver that receives information on a candidate Antenna Port (AP) set including candidate APs selected from among a plurality of APs, information on an active AP set including active APs selected from the candidate AP set, and downlink CSI on the active APs; and an AP channel matrix recovery unit that determines a maximum singular vector of downlink channel matrix for the plurality of APs using the downlink CSI on the active APs.
A Channel State Information (CSI) processing apparatus for a transmitter in a wireless communication system using distributed antennas has two main parts: a feedback receiver and an antenna channel matrix recovery unit. The receiver obtains information about a candidate antenna set, which is a subset of available antennas, information about an active antenna set, selected from the candidate set, and downlink CSI for those active antennas. The recovery unit uses this CSI to determine the maximum singular vector of the downlink channel matrix for all antennas.
20. The CSI processing apparatus of claim 19 , wherein the candidate AP set is selected in consideration of slow fading, and wherein the active AP set is selected from the candidate AP set in consideration of fast fading.
In the Channel State Information (CSI) processing apparatus of a transmitter, where a feedback receiver gets information on candidate and active antenna sets and downlink CSI, and an antenna channel matrix recovery unit calculates a maximum singular vector, the candidate antenna set is determined considering slow fading, representing long-term signal strength. The active antenna set is selected from the candidate set taking fast fading into account, which reflects short-term channel variations.
Unknown
December 9, 2014
Browse 5M+ US patents with plain-English claim translations and AI-generated analysis.